Hydrate reducing and lubrication system and method for a fluid flow system

ABSTRACT

A system and method for lubricating fluid flow apparatus utilizing a hydrate-reducing chemical.

BACKGROUND

[0001] This invention relates to a hydrate reducing and lubrication system and method for a fluid flow system.

[0002] In large fluid processing systems, heavy machinery, including pumps, compressors, and motors, are utilized. This equipment, of course, has components, such as bearings and seals, that have to be lubricated. Oil, or oil based products, are often used as a lubricant, which is expensive and requires additional equipment, such as coolers and pumps. Moreover, any oil that leaks past the seals and bearings of the equipment has to be reclaimed, which further adds to the costs. These problems are especially acute in connection with subsea, or offshore, oil and gas recovery systems, since the lubricants have to be transported from land to the offshore system and stored in relatively large vessels.

[0003] Therefore, what is need is a lubrication system for machinery of the above type which eliminates the need for oil and the above attendant problems.

SUMMARY

[0004] According to the system and method of the present invention, a hydrate-reducing chemical is passed into at least a portion of the equipment for lubricating same.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The drawing is an diagrammatic view of a system according to an embodiment of the present invention.

DETAILED DESCRIPTION

[0006] An embodiment of the present invention will be described in connection with a hydrocarbon recovery system, shown, in general by the reference numeral 10. The system 10 is designed to recover hydrocarbon fluid, such as oil and gas, from a well 12, and, to this end, one end of a conduit 14 extends from the well for transporting the recovered fluid from the well. A slug catcher 16 is connected to the other end of the conduit 14 for removing foreign matter, such as rock and sand, from the recovered fluid. In the slug catcher 16, the gaseous portion of the recovered fluid rises to the upper portion of the slug catcher, and the liquid portion descends to the lower portion thereof.

[0007] A conduit 20 extends from the upper portion of the slug catcher 16 for transporting the separated gas to the inlet of a compressor 22 for passing the gas to an outlet conduit 24 that extends from the outlet of the compressor. The gas passes, via the conduit, 24 to storage facilities, or the like.

[0008] Similarly, one end of a conduit 26 is connected to the lower portion of the slug catcher 16, and a pump 28 is connected to the other end of the conduit for pumping the separated liquid through the conduit 26 and to an outlet conduit 30 extending from the outlet of the pump 28. The liquid passes, via the conduit 30, to storage facilities, or the like. It is understood that the recovered gas and liquid can be combined after they exit the compressor 22 and the pump 28, respectively, and before they are stored. Two motors 32 and 34 are operatively connected to the compressor 22 and to the pump 28, respectively, for driving them.

[0009] A tank 40 is provided which contains a chemical to minimize and or eliminate hydrate formation in the conduits 20, 24, 26, and 30, the compressor 22, and the pump 28 during the above-described operation. A non-limitative example of this chemical is a monoethylene gycol (MEG). A conduit 42 extends from the storage tank 40 to the slug catcher 16 for transporting the MEG to the slug catcher where it mixes with the recovered gas and liquid. The MEG, with the gas and liquid, then passes, via the conduits 20 and 26, to the compressor 22 and the pump 28, respectively, before it is discharged, with the gas and liquid, to the conduits 24 and 30, respectively for passage to the storage facilities.

[0010] A conduit 46 extends from the conduit 42 and branches into four branch conduits 46 a, 46 b, 46 c, and 46 d which extend to two inlets in the motor 32 and two inlets in the compressor 22, respectively. These inlets are in communication with the bearings and seals of the compressor 22 and the motor 32, and normally receive oil for lubricating the bearings and the seals. However, the need for oil is eliminated since the MEG performs the lubricating function.

[0011] Similarly, a conduit 50 extends from the conduit 42 downstream of the conduit 46 and branches into four branch conduits 50 a, 50 b, 50 c, and 50 d which extend to two inlets in the motor 34 and two inlets in the pump 28, respectively. These inlets are in communication with the bearings and seals of the pump 28 and the motor 34, and normally receive oil for lubricating the bearings and the seals. However, the need for oil is eliminated since the MEG lubricates the pump 28 and the motor 34.

[0012] A discharge line 52 is connected to the lubrication outlets of the motor 32 and the compressor 22, via branch conduits 52 a, 52 b, 52 c, and 52 d, respectively. Also, a discharge line 54 is connected to the lubrication outlets of the motor 34 and the pump 28, via branch conduits 54 a, 54 b, 54 c, and 54 d, respectively. It is understood that the discharge lines 52 and 54 can be connected to the slug catcher 16, the well head, or any ancillary equipment.

[0013] It is understood that a booster pump, or the like, can be provided in the conduits 42, 46, 50, 52 and 54 as needed to pump the MEG in the manners discussed above.

[0014] Thus, according to the above embodiment, the MEG functions to both lubricate the compressor 22 the pump 28, and their motors 32 and 34; as well as reduce hydrate formation in the conduits 20, 24, 26, and 30, the compressor 22, and the pump 28. Thus the need for oil lubrication of the compressor 22, the pump 28, and the motors 32 and 34 is eliminated. Also, any of the MEG that leaks past the bearings and/or seals of the above components does not need to be reclaimed since it can be discharged back into the compressor 22 and/or the pump 28. Moreover, the above embodiment eliminates the need for additional storage facilities, or associated equipment that is required when oil is used as a lubricant.

[0015] It is understood that variations may be made in the foregoing without departing from the scope of the invention. For example, the above embodiment is not limited to oil and gas applications but is equally applicable to any application in which it is desirable to use a chemical, such as MEG, to minimize and or eliminate hydrate formation in the conduits and/or equipment. Also, the above references to “conduit” are not meant to be limited to any particular fluid flow device, such as hoses, tubes, and the like, and any such device or devices can be used throughout the system. Further, the system and method of the present invention are not limited to use with pumps, compressors and motors, but is equally applicable to any other similar type of equipment.

[0016] Since other modifications, changes, and substitutions are intended in the foregoing disclosure, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention. 

What is claimed is:
 1. A lubrication method for fluid processing apparatus, the method comprising passing a quantity of a hydrate-reducing chemical into at least a portion of the apparatus for lubricating same.
 2. The method of claim 1 further comprising passing an additional quantity of the chemical through the apparatus to reduce the formation of hydrates in the apparatus.
 3. The method of claim 2 wherein the apparatus includes a pump and wherein the additional quantity of material is passed through the pump during its pumping operation.
 4. The method of claim 2 wherein the apparatus includes a compressor and wherein the additional quantity of material is passed through the pump during its pumping operation.
 5. The method of claim 3 wherein the apparatus is adapted to pump fluid through a conduit and wherein the chemical is added to the fluid and is pumped, with the fluid, through the conduit and the apparatus.
 6. The method of claim 1 wherein the chemical is introduced into the apparatus through lubrication inlets provided in the apparatus.
 7. The method of claim 1 further comprising discharging the chemical from lubrication outlets provided in the apparatus after the chemical has lubricated the apparatus.
 8. The method of claim 7 further comprising passing the discharged chemical to external equipment.
 9. The method of claim 1 wherein the fluid contains hydrocarbons recovered from an oil and gas well, and further comprising separating foreign matter from the fluid in a separator.
 10. The method of claim 9 wherein the step of separating is before the step of passing.
 11. The method of claim 1 wherein the fluid contains gas and liquid and further comprising the step of separating the gas from the liquid.
 12. The method of claim 1 wherein the chemical is monoethylene gycol.
 13. A fluid flow system comprising a conduit, apparatus for flowing a fluid through the conduit, and means for passing a hydrate-reducing chemical to the apparatus for lubricating same.
 14. The system of claim 13 wherein the apparatus comprises a housing and lubrication inlets and outlets formed in the housing, the chemical being introduced into the inlets and discharged from the outlets.
 15. The system of claim 14 further comprising means for passing the discharged chemical to external equipment.
 16. The system of claim 13 wherein the apparatus includes a pump for pumping the fluid through the conduit, and further comprising means for passing the chemical into the fluid so that the fluid and the chemical are pumped through the conduit and the pump to reduce the formation of hydrates in the conduit and the pump.
 17. The system of claim 13 wherein the apparatus includes a compressor for flowing the fluid through the conduit, and further comprising means for passing the chemical into the fluid so that the fluid and the chemical are flowed through the conduit and the compressor to reduce the formation of hydrates in the conduit and the compressor.
 18. The system of claim 13 wherein the apparatus comprises a pump and/or compressor, and a motor for driving same.
 19. The system of claim 13 wherein the fluid contains hydrocarbons recovered from an oil and gas well, and further comprising a separator for separating foreign matter from the fluid.
 20. The system of claim 13 wherein the fluid contains gas and liquid, and further comprising a separator for separating the gas from the liquid. 